1. Field of the Invention
The present invention relates to an automatic control valve, and more particularly to an automatic flow control valve having an improved construction, by which the quantity of fluid can be more precisely controlled according to the necessity even without disassembling the valve, and which has a relatively large range of controlling the quantity of fluid, so that the valve can flexibly cope with a change in a piping system, and can be repaired and maintained in simple and easy manner.
2. Description of the Prior Art
In a general piping system, how precise quantity of fluid can be supplied to sections of the piping system connected with each other is a very important problem. In order to solve the problem, when the piping system is designed and constructed, a complicated process of repetitive calculations of various factors such as diameters of pipes and frictional loss has been necessary up to now. Further, even after the piping system is constructed in the complicated process as described above, when it is necessary to change the quantity of fluid or when there happens a change in the quantity of fluid due to such reasons as an accumulation of alien material according to aging of the piping system, the piping system has to be subjected to a balancing treatment through a complicated process.
However, even though the automatic flow control valve has been balanced to a certain degree through the complicated process as above, it is just a temporary balance, and the piping system may be come into an unbalanced state when even a small change happens in the system. Therefore, developed and used has been an automatic flow control valve, which can flexibly cope with such a change of the system and thereby enable a constant quantity of fluid to flow therein.
FIG. 1 shows an exemplary conventional automatic flow control valve. Referring to FIG. 1, the conventional automatic flow control valve includes a housing 40 having a fluid channel 41 formed therein, a ring member 53 fixed in the fluid channel 41, a control member 50 slidably fitted in the ring member 53, and a spring 55 elastically supporting the control member 50 toward an entrance port 41a of the fluid channel 41. The control member 50 has a shape of a cup and has a plurality of slots 51, which are formed through a side portion of the control member 50 and through which fluid can pass. In this case, when the control member 50 is moved forward and backward centering around the ring member 53 by the pressure changes of fluid in the fluid channel 41, an area, through which the fluid passes, is changed according to the number of the slots 51 exposed to the side of the entrance port 41a. Further, the control member 50 is classified into several kinds thereof according to the dimensions thereof, so that the control member 50 of a corresponding size can be fitted in and can control the quantity of fluid passing through a flow control valve of a predetermined size.
In result, when the pressure of fluid introduced in the valve increases, the control member 50 is moved backward against the elastic force of the spring 55, so that the number of the slots 51 exposed to the side of the entrance port 41a is reduced and thereby the fluid at a high pressure passes through the reduced slots with a reduced total area. In contrast, when the pressure of fluid decreases, the control member 50 is moved forward by the elastic force of the spring 55, so that the number of the slots 51 exposed to the side of the entrance port 41a increases and thereby the fluid at a low pressure passes through the increased slots with an increased total area. Therefore, the quantity of fluid flowing through the fluid channel can be maintained always constant by the automatic control of the flow control valve.
However, when it is necessary to change the quantity of fluid passing through the automatic flow control valve due to such reasons as a change of the piping system while the automatic flow control valve is used, the automatic flow control valve has to be completely disassembled one component by one component. Thereafter, the control member 50 has to be replaced by one having a different size, and then the valve has to be reassembled. Such a complicated labor of assembling and disassembling the automatic flow control valve causes inconvenience to a user of the valve. Moreover, the flow control method by a replacement of the control member 50 is problematic in that the quantity of fluid cannot be precisely controlled but can be controlled only between a few steps by several kinds of control members the control member 50, which are manufactured in advance.
Furthermore, in the automatic flow control valve, since the fluid-passing area is controlled while the control member 50 is slid in contact with the inner circumference of the ring member 53 by the pressure of the fluid, there is generated metallic noise, which is very unpleasant, due to the friction between the control member 50 and the ring member 53. Further, since the fluid-passing area is controlled by means of the slots 51 formed through the control member 50, which have a relatively small area and thereby have a relatively small range of controlling the quantity of fluid, it is difficult to flexibly cope with the change of pressure.
In the conventional automatic flow control valve as described above, when alien material has been accumulated in the valve after the valve is used for long time, the valve has to be disassembled one component by one component, the alien material is eliminated, and then the valve is assembled again. Therefore, it can be said that it is very difficult to repair and maintain the conventional automatic flow control valve.
Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and an object of the present invention is to provide an automatic flow control valve having an improved construction, by which the quantity of fluid can be more precisely controlled according to the necessity even without disassembling the valve, and which has a relatively large range of controlling the quantity of fluid, so that the valve can flexibly cope with a change in a piping system.
It is another object of the present invention to provide an automatic flow control valve having an improved construction, which generates no operational noise but can be quietly operated, and which can be repaired and maintained in simple and easy manner.
In order to accomplish this object, there is provided an automatic flow control valve comprising: a valve body having a fluid channel and a chamber, which are formed in the valve body and communicate with each other, the fluid channel having an entrance port and an exit port; a diaphragm disposed in the chamber and having a fluid channel switching shaft connected to one surface of the diaphragm; a spring elastically supporting the diaphragm in a direction of opening the fluid channel; and a flow control means assembled with the valve body and extending toward a portion of the fluid channel, which is disposed in front of or behind the fluid channel switching shaft, wherein a fluid transfer hole communicating with an entrance port is formed at an upper portion of a side surface of the chamber, so that an opening degree of the fluid channel can be automatically controlled by the fluid channel switching shaft connected with the diaphragm when the diaphragm is operated by pressure of the fluid transferred through the fluid transfer hole.
It is preferred that, in the automatic flow control valve, the flow control means comprises a cover detachably assembled at one side of the valve body, and an adjusting screw, which is screw-assembled with the cover and protrudes toward the fluid channel, so as to adjust an opening degree of the fluid channel, so that the quantity of fluid passing through the automatic flow control valve can be controlled by tightening and loosening the adjusting screw.